St. George, Utah, USA
The Hurricane Hydro Electric Plant, which is fed from the Virgin River diversion dam was originally supplied and commissioned in 1987. Reliable operation of the plant is critical for the operators Washington County District Water Conservancy (WCWCD), as its outflow allows them to meet their obligation to provide a set flow rate in the river for downstream consumers and wildlife. Gilkes were invited to review the system with a view to upgrading the control system and governor to improve reliability following 30 years of operation.
The mechanical aspects of the turbine were found to be operating in good condition despite constant attack from the sediment laden water abstracted from the river. The Turgo turbine has a reputation for excellent abrasion resistance and this was in evidence here. Many parts that are in constant contact with the water are still originals from when the turbine was supplied.
The original spear valve actuators had become unreliable and frequently needed maintenance, therefore these were upgraded to modern modulating rotary actuators to provide reliable control of flow through the turbine. A complete new control panel suite was proposed replacing the existing control and switchgear.
The deflector control arrangement was completely revised to facilitate the new control philosophy. Control of the deflectors is by a new digital governor, which works to precisely match the generators speed to the grid prior to synchronisation. Generator start up is now possible at any turbine flow rate above the minimum flow of the system, including at full turbine flow.
The new control system is fully automated and is expected to improve the annual energy production of the generator significantly, due to higher reliability and lower operator dependence.
SCOPE OF SUPPLY
- Full Control and Switching Panel suite designed to fit over existing cable ducts
- Electric Spear valve actuators replacing worn out originals
- Hydraulic control module for deflector control
- New hydraulic actuator for Turbine deflectors
- Bespoke control philosophy as dictated by operators requirements
- Originally Commissioned 1987
- Upgrade 2017
- Power 605 kW
- Net Head 333 ft
- Flow 25 cfs
- Turbine Type Twin Jet Turgo